1. Field of the Invention
The present invention relates to a generator apparatus and, in particular, to a generator apparatus capable of outputting a comparatively large direct current and detecting the occurrence of an abnormality with ease.
2. Description of the Related Art
A generator apparatus having a generator which is driven by an engine or the like has been conventionally widely employed as the power supply of an electric appliance especially used for outdoor works and for leisure-time activities. Further, in recent years, the uses of the generator apparatus are spreading also to the back-up power supply, that is, the so-called uniterruptible power supply (UPS) for computers and the like. When the generator apparatus of this kind is constructed as a generator apparatus for outputting a direct current, there is a tendency that the generator is required to be small in size and to be able to output a comparatively low voltage and a large current. In the generator required to output a large current like this, a larger size of wire for an output winding is needed and a higher level of consideration is required to be given also to a dielectric breakdown voltage between windings and a material for insulator.
Hence, the present applicant proposed a generator apparatus that could be reduced in the wire diameter of an output winding and could be reduced in the capacity of a power device (Japanese Utility Model Registration No. 2511843). In a device in accordance with this registered utility model, a plurality of power supply units independent of each other are formed, respectively, of a plurality of output windings that are wound independently of each other around the same iron core and thyristor bridge rectifier circuits connected to the plurality of output windings, and the outputs of the power supply units are connected in parallel, thereby being integrated into one output.
When the generator apparatus disclosed in the above-described patent document is used for charging a battery, that is, when a battery is connected as a load of the generator, a charging voltage needs to be changed according to the voltage specification of the battery. For this reason, it is thought that a selector switch is provided to change the output of the generator for each battery to be connected. However, it is complicated to check the voltage specification and to operate the selector switch every time a battery is connected. Further, if an operation of changing output is performed by mistake, the battery is excessively charged or cannot be sufficiently charged.